One vertex per element, one color per generator, with an edge from x to x·s.
(3,8)(4,6)(9,10)(11,16)(12,20)(13,17)(14,18)(15,21)(19,23)(22,24) involution — undirected(1,2)(3,4)(5,7)(6,8)(9,11)(10,13)(12,19)(14,17)(15,23)(16,18)(20,22)(21,24)(25,26,30,31)(27,29,33,38)(28,32,36,39)(34,37,40,35)(1,3,5,8)(2,6,7,4)(12,21)(15,20)(19,24)(22,23)(26,31)(27,33)(32,39)(34,40)(2,7)(3,8)(9,12,14,21)(10,15,18,20)(11,19,17,24)(13,23,16,22)(25,27)(26,29)(28,34)(30,33)(31,38)(32,37)(35,39)(36,40)(1,4)(2,3)(5,6)(7,8)(9,11)(10,16)(12,19)(13,18)(14,17)(15,22)(20,23)(21,24)(25,28)(26,32)(27,34)(29,37)(30,36)(31,39)(33,40)(35,38) involution — undirected(1,2)(3,6)(4,8)(5,7)(9,13,14,16)(10,17,18,11)(12,22,21,23)(15,19,20,24)(25,29)(26,33)(27,31)(28,35)(30,38)(32,34)(36,37)(39,40)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.